Safety system for swimming pool

ABSTRACT

A safety system for a swimming pool is disclosed which includes a platform guided for vertical movement in the pool; a ballast system attached to the platform; a pump; an inlet flow path for the pump, one end of the inlet flow path in communication with the pump and the other end of the inlet flow path in communication with the water in the pool; an outlet flow path for the pump, one end of the outlet flow path in communication with the pump, and the other end of the outlet flow path in communication with the water in the pool; a first diversionary flow path communicating at one end thereof with the inlet flow path and at a second end thereof with the ballast system; a second diversionary flow path communicating at one end thereof with the outlet flow path and at a second end thereof with the ballast system; and control means operable to control the flow of water in the inlet flow path, the outlet flow path, the first diversionary flow path, and second diversionary flow path for selectively emptying and filling the ballast system with the water from the pool, whereby the platform may be selectively caused to rise and sink. Preferably, the control means includes: at least a first operating mechanism movable between first and second position when it is desired to draw water from the ballast system and thereby raise the platform; a first normally open valve positioned in the inlet flow path and movable to a closed position in response to movement of the first operating mechanism between its first and second position, and a second normally closed valve positioned in the first diversionary flow path and movable to an open position in response to the movement of the first operating mechanism between its first and second position. Additionally, the control means further includes a follower system responsive to the movement of the platform for returning the aforementioned operating mechanism to its first position (and the valves controlled thereby to their normal positions) when the platform reaches a first predetermined level such as the top of the pool. In this manner, water will circulate from the inlet flow path to the outlet flow path in the normal filtering process once the platform has reached its predetermined position. Similar control mechanism and follower mechanism are provided to temporarily divert water flow into the ballast system when it is desired to sink the platform and to automatically return the system to the normal filtering operation, once the platform has reached the bottom of the pool. As a further feature of the invention, level selection means are provided and cooperate with the aforementioned control means for maintaining the safety platform at a predetermined, desired level in the pool.

Glorisi m] 97 v[45] sgpt 259 SAFETY SYSTEM FOR SWIMMING POOL [76] Inventor: Frank Glorisi, 607 Remsen Ave.,

North Brunswick, NJ. 08902 22 Filed: June 8, 1972 21 Appl. No.: 260,765

[52] US. Cl. 4/17213 [51] Int. Cl...; E04h 3/16, 'EO4h 3/18 [58] Field of Search 4/172, 172.11, 172.12, h 4/l72.l3

[56] References Cited v UNITED STATES PATENTS 3,184,763 5/1965 Kennedy 4/l72.13 3,235,885 2/1966 Barnes 4/172 3,242,503 3/1966 Russo 4/172.13 3,309,716 .3/1967 Merritt 41172.17 X 3,377,632 4/1968 Peterson 4/172.13 3,423,768 1/1969 Glenn 4/172.13 3,590,399 7/1971 Madden 4/172.13

Primary Examiner-Henry K. Artis -AttorneyLawrence I. Lerner et a1.

[5 7 ABSTRACT A safety system for a swimming pool is disclosed which includes a platform guided for vertical movement in the pool; a ballast system attached to the platform; a pump; an inlet flow path for the pump, one end of the inlet flow path in communication with the pump and the other end of the inlet flow path in communication with the water in the pool; an outlet flow path for the pump, one end of the outlet flow path in communication with the pump, and the other end of the outlet flow path in communication with the water in the pool; a first diversionary flow path communicating at one end thereof with the inlet flow path and at a second end thereof with the ballast system; a second diversionary flow path communicating at one end thereof with the outlet flow path and at a second end thereof with the ballast sys tem; and control means operable to control the flow of water in the inlet flow path, the outlet flow path, the

first diversionary flow path, and second diversionary flow path for selectively emptying and filling the ballast system with the water from the pool, whereby the platform may be selectively caused to rise and sink. Preferably, the control means includes: at least a first operating mechanism movable between first and second position when it is desired to draw water from the ballast system and thereby raise the platform; a first normally open valve positioned in the inlet flow path and movable to a closed position in response to movement of the first operating mechanism between its first and second position, and a second normally closed valve positioned in the first diversionary flow path and movable to an open position in response to the movement of the first operating mechanism between its first and second position. Additionally, the control means further includes a follower system responsive to the movement of the platform for returning the aforementioned operating mechanism to its first position (and the valves controlled thereby to their normal positions) when the platform reaches a first predetermined level such as the top of the pool. In this manner, water will circulate I from the inlet flow path to the outlet flow path in the normal filtering process once the platform has reached its predetermined position.

Similar control mechanism and follower mechanism are provided to temporarily divert water flow into the ballast system when it is desired to sink the platform and to automatically return the system to the normal filtering operation, once the platform has reached the bottom of the pool.

As a further feature of the invention, level selection means are provided and cooperate with the aforementioned control means for maintaining the safety platform at a predetermined, desired level in the pool.

12 Claims, 6 Drawing Figures PATENTED SEPZSWS SMET30f3 ll Y SAFETY SYSTEM FOR'SWIMIVIING POO FIELD OF THE INVENTION This invention relates to swimming pools and more particularly" to a safety platform for a swimming pool which can be selectively raised to close the pool; selectively lowered to the bottom thereof when it is desired to utilize the pool; and selectively maintained at any desired level therebetween for changing the effective depth of the pool.

BACKGROUND OF THE INVENTION In recent years, with the ever increasing amount of leisure time available, swimming as a recreational activity has enjoyed a significant increase in populatiry. This phenomena is further illustrated by the ever increasing number of private pools, of the in-ground and above-ground type, which are owned by individuals.

A significant problem relating to the safe and efficient use of swimming pools concerns the need for a cover therefor which can easily be removed when it is desired to use the pool and which, at the same time, can be easily installed in place when it is desired to close the pool, especially to make it inaccessible tochildren.

' In this regard, various systems have-been proposed wherein separate covers can be used in conjunction with the pool, and which are, in reality, discarded when the pool is in use. When it is desired to close the pool, the'cover is physically placed back on the pool. Clearly, this type of system is unsatifactory since separate provision must be made for the storage of the cover when not in use.

Other systems which have been proposed suggest that a platform member might be selectively movable between the bottom and top of the pool when it is desired to use or cover the pool respectively. Although this principle is fundamentally sound, the various prior art attempts to mechanize same have been cumbersome, complicated, expensive, difficult to implement and difficult to utilize especially by the average, unsophisticated consumer.

For example, some of these last named type of system have suggested that a gas ballast system to be employed inconnection with the'safetyplatform. When gas is supplied to the ballast system, the platform rises to the top of the pool to cover same and prevents entry into the pool. When the gas is withdrawn, the platform sinks to the bottom of the pool making the pool accessible for use. One illustrated example of this type of system is found in U.S. Pat.No. 3,423,768- issued to l... E. Glenn Jan. 28, 1969 entitled Safety Platform for Swimming Pools. With the Glenn Patent, a separate supply of compressed gas is used in conjunctionwith a ballast system provided in association with the safey platform Although such SySl1llli feasible the need for the separate supply of compressed gas makes such a system undesirable. 7

Another system which employs a ballast principle to selectively float or sink the platform in a swimming pool is illustrated in U. 8. Pat. No. 3,242,503 issued Mar. 29, 1966 to L. Russo. Although the scheme illustrated in the Russo patent does not require the employment of a separate source of compressed gas, but instead takes advantage of the pumping system normally utilized for circulating the pool water through a filtering system; the system illustrated for example in the Russo patent, is manually operable and does not include control means for automatically regulating the flow of water in the various paths thereof, and furthermore does not include a system for automatically and simply establishing a pre-selected level for the safety platform thereof.

SUMMARY OF THE INVENTION Like the system of the aforementioned Russo US. Pat. No. 3,242,503, the instant invention employs a water pumping system which is primarily utilized for recirculating the pool water through a filtering system for the additional function of selectively filling and emptying a ballast system to cause a safety platform to sink or rise within the swimming pool. However, in contradistinction to the prior art represented for example, by the aforementioned Russo patent, tne instant invention further includes control means for automatically controlling the flow of. water in the various inlet, and outlet, and diversionary flow paths forming a part of the system hereof, for selectively emptying and filling the ballast system with water from the pool.

Specifically, the system of the instant invention includes an inlet flow path and outlet flow path, which together establish a normal flow path for the water in the pool through the pumping and filtering system used in conjunction therewith. Additionally, first and second diversionary flow paths are established to draw water from the aforementioned ballast system when it is desirable to float the safety platform or to fill the aforementioned ballast system with water from the pool when it is desired to sink the safety platform hereof. With respect to the operation of the system to float the safety platform, the control means includes a first operating mechanism movable between first and second positions to properly set valves provided in the inlet flow path and first diversionary flow path whereby water will be drawn from the ballast system and pumped into the pool itself, and the safety platform will rise. Similarly, and in connection with the operation of causing the safety platform to sink, a second operating mechanism is provided which is movable between a first and second position to automatically set valves in the outlet flow path and a second diversionary flow path such that water drawn from the pool will be diverted to the ballast system to cause the safety platform to sink.

In accordance with a further feature of the invention, follower means responsive to the movement of the safety platform are provided for automatically returning the aforementioned operating mechanisms to their first positions when the platform reaches a preselected level within the pool. In the manner, when the follower system returns the aforementioned operating mechanisms to their first positions, all of the previously mentioned valves are returned to their normal status, and the pumping system will automatically revert to its primary function of recircularing the pool water through a filter. As noted, these operations take place automaticallly once the safety platform reaches the predetermined level (be it the top or bottom of the pool), without the user having to make any adjustment.

As a further feature of the invention, level selection means are provided in association with the aforementioned control means for automatically maintaining the safety platform at a predetermined desired level in the pool. Briefly speaking, and as will be described in greater detail, such level selection means comprises actuating means for intermittently operating the aforementioned first and second operating mechanism in response to deviations in the platform level from a predetermined desired level. For example, if the mechanism were set to maintain the level of the platform at two feet from the top surface, and for example, a child stepped on the safety platform, causing the platform to begin to sink; the first aforementioned operating mechanism will be automatically moved to its second positioned to set its respective valves in such a manner that water will be drawn from the ballast system, and the platform would begin to rise to compensate for the additional weight of the child. If and when the child stepped off of the platform and the platform began to rise as a consequence thereof; the aforementioned second operating mechanism will be automatically moved to its second position to set the valves responsive thereto in such a manner that water will be automatically fed to the ballast system to cause the platform to begin to sink to compensate for the loss in weight. As will be explained in greater detail, the system continues to operate in this mode with the platform oscillating about a predetermined level.

Accordingly, it is an object of the instant invention to provide a safety system for a swimming pool, which makes use of a pumping system thereof, normally utilized for recirculating pool water, for the additional function of selectively emptying or filling a ballast system in such a manner as to selectively sink or rise a safety platform associated therewith.

Another object of the invention is to provide such a system which includes control means for automatically establishing desired flow paths inan inlet flow path, in an outlet flow path and diversionary flow paths associated therewith.

Yet another object of the instant invention is to provide such a system which further includes movable operating mechanism for automatically setting valve positions in the aforementioned inlet, outlet and diversionary flow paths.

Still another object of the instant invention is to provide such a system which includes automatic follower means for automatically returning the aforementioned operating mechanisms to initial positions when the safety platform reaches predetermined levels.

Yet another object of the instant invention is to provide such a system which further includes level selection means cooperating with the control means for maintaining the safety platform at a predetermined desired level intermediate the top and bottom of the pool.

Other object and a fuller understanding of the instant invention may be had by referring to the following description and drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of swimming pool incorporating the safety platform system of the instant invention.

FIG. 2 is a top plan view of the swimming pool and platform illustrated in FIG. 1.

FIG. 3 is a flow diagram illustrating the operation of the instant invention.

FIG. 3A is a partial side view of a portion of the mechanism of the instant invention.

FIG. 4 is a flow diagram of the system of the instant invention.

FIG. 5 is a flow diagram of the instant invention, and further illustrates an added feature thereof.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Turning to the Figures and initially to FIGS. 1 and 2, there is shown a swimming pool 10 incorporating a safety platform broadly designated 12 constructed in accordance with the instant invention. The pool 10 may be of the in-ground or above-ground type, and includes a liner 14 appropriately supported by frame members designated 16. The safety platform 12 includes a ring or frame 18 conforming to the planar configuration of the pool in which it is employed, and a screenlike surface 20 secured thereacross. As best illustrated in FIG. 1, the ring 18 includes a plurality of collar members 22 disposed thereabout. Collar members 22 are slidably positioned on support columns 24, which, in turn are supported by the frame members 16, for example, by being telescopically received therein in the manner shown in FIG. 1. In this manner, and by means of the ballast system and control means therefor, to be described in greater detail, the safety platform 12 is vertically guided for movement between the bottom and top of pool 10, or any position therebetween.

Secured to the undersurface of safety platform 12 is a ballast system broadly designated 26 including a pilot ballast tank 28 and a plurality of secondary ballast tanks 30 distributed around the outside perimeter of the platform 12. Hoses 32 interconnect the pilot tank 28 and the secondary ballast tanks 30. Also known in FIG. 2 is a pump 34, a filter 36, an inlet flow path 38, an outlet flow path 40 and a conduit 42 forming a portion of diversionary flow paths to be described in detail with respect to FIGS. 3 through 5.

Inlet flow path has one end thereof 44 in communication with the water in the pool 10 and a second end thereof 46 in communication with the pump 34. In like manner, outlet flow path 40 has one end 48 in communication with the pump 34 (via the filter 36 and the intermediate conduit 49) and a second end 50 in communcation with the water in the pool 10. Conduit 42 includes one end 52 in communication with the pilot ballast tank 28 while the other end communicates with the remainder of the pumping system in a manner to be further described with respect to FIGS. 3 through 5.

In a normal operation, and as is well known in the art, water is drawn from the pool by the pump 34 through the conduit 38 and circulated through the filter 36 back to the pool by way of the conduit 40.

Turning to FIG. 3 the control means of the instant invention is seen to include a first operating mechanism 54 slidably movable on a rod 56, the purpose of which will be further described. In the illustrated embodiment the operating mechanism 54 is in the form of a cylindrical sleeve slidable between a first position illustrated at 54 and a second position shown in solid line form at 54. Sleeve 54 is linked by a pair of connecting members 58, 60 to first and second rotatable valves 62 and 64 respectively, which control their operation in a manner to be further described.

In similar fashion, the control means of the invention includes a second operating mechanism shown as a sleeve member 66 (FIG. 4) slidably positioned on a rod 68 (to be further described) between a first position illustrated in phantom at 66' and the solid line position illustrated at 66. By connecting members 70 and 72, the sleeve 66 is operably connected to rotatable valve Wind 76 which are operated by the movement ofthe sleeve 66 in a manner to be further described.

It will be seen that the first valve 62 ispositioned in the inlet flow path 38 andis normally open valve (as shown in FIG. 4) such that under normal conditions water may be drawn from the pool end 44 of the inlet flow path 38 toward the pump 34. The second valfe 64 is a normally closed valve (illustrated in its closed position in FIG. 4) positioned in a first diversionary flow path 78 including a conduit 80 and the aforementioned conduit 42, the far end 52 of which communicates with the pilot ballast tank 28 of FIGS. 1 and 2. It will be understood that when he operating sleeve 54 is in its upper phantom position 54' of FIG. 3, the valve 62 is in its normally open condition, and the valve 64 is in its the common aforementioned conduit 42, the far end 52 of which communicates with the pilot ballast tank 28. his to be understood that when the second operating sleeve 66 is in its downward phantom position 66', (shown in FIG. 4) that the third valve 74 is in a normally closed state and the fourth valve 76 is in its normally open state both of which are illustrated in FIG. 3. However, when the operating sleeve 66 is raised to the solid line position in FIG. 4, the valve 74 is rotated to its open state and the valve 76 rotated to its closed state, both of which are illustrated in FIG. 4. 12

As mentioned previously, the first operating sleeve 54 is slidably movable on rod 56 between first and sec- "ond positions, which, it will be appreciated are defined As shown in FIG. 3A, rod 56 is linked to the safety platform 12 by a linkage arrangement including rods 86 and 88. Thus, if safety platform 12 should rise, the rod 56 will rise. Similarly, any downward movement of the safety platform l2will be followed by the rod 56. It will also be appreciated that although one-to-one relationship is shown in FIG. 3A, if desired the rod 56 may move in some proportion to the amount of movement experienced by the safety platform 12. In similar fashion, the rod 68 of FIG. 4 is connected to the safety platform 12 by a direct linkeage arrangement (not shown). Thus rod 68 follows the movement of the safety platform 12. For purposes to be further described, rod 56 carries a stop member 90, and rod 68 of FIG. 4 carries a stop member 92.

To understand the basic operation of a system of the instant invention, attension is drawn to FIG. 5. This Figure, while also including level selection means designated 94 to be described in greater detail, also shows the entire system including both operating sleeves 54 and 66 and their associated valves. Thus, in FIG. 5 the first operating mechanism 54 is in its uppermost first position 54', such that the valve 62 is in its normally open condition and the valve 64 is in its normally closed position. Similarly, the second operating sleeve 66 is in its downward first position 66', such that the valve 76 is in its open condition and the valve 74 is in its closed condition. With this arrangement, water from the pool will be drawn through the inlet flow path 38 through the pump 34, filter 36 and recirculated back to the pool 10 through the outlet flow path 40.

Now let it be assumed for the sake of illustration, that the safety platform 12 presently resides at the bottom of the pool 10, in a manner depicted in FIG. I, and that it is desired to raise the platform 12 to the top of the pool. The user would simply grasp the handle provided on the sleeve 54 and slide the handle 54 downward to its solid line position shown in FIG. 3. This would have the effect, as explained previously, of rotating the valve 62 to its closed position, and rotating the valve 64 to its open condition, both states being depicted in FIG. 3. Thus, the inlet flow path 38 will be closed, and the first diversionary flow path 78, comprising the conduit 80 and the conduit 42, will be opened whereby water will be drawn from the pilot ballast tank 28 (and the secondary ballast tanks 30) and circulated through the pump 34, filter 36 and the outlet flow path 40 back to the pool. Of course, it will be appreciated that as water is withdrawn from the ballast tanks, air will be drawn therein through the air vents 96 associated with each secondary ballast tank 30. Thus, the ballast tanks will become buoyant, and platform 12 will rise toward the surface.

As the platform 12 rises, the rod 56 of FIG. 3A will also rise, and eventually, when the platform 12 reaches the top of the pool, the stop member will engage the operating sleeve 54 and move it back up to its first position illustrated in FIG. 5 at 54'. Of course, as the operating sleeve 54 moves back to the position illustrated at 54, the valve 62 and 64 will be returned to their normally open and normally closed positions respectively, and the pumping system will then return to simply recirculating the water through the inlet flow path 38, the filter 36, the outlet flow path 40 and back to the pool. It will be appreciated that this conversion will take place automatically by virtue of the follower rod 56 and without any attention required on the part of the user.

Now let it be assumed that the user wishes to return the platform 12 to its lower position illustrated in FIG. 1. In this case, the operator simply raises the second operating sleeve 66 from its first position illustrated at 66 in FIG. 5 to its second position illustrated in solid line at 66 in FIG. 4, in which case the valve 74 will rotate to its open condition and the valve "76 will rotate to its closed position. In this manner, the outlet flow path 40 will be closed, and the second diversionary flow path 82 comprising the conduit 84 and the common conduit 42 will open such that water will be flowing from the pool through the inlet flow path 38, through the pump 34, through the filter 36, and through the second diversionary flow path 82 to the pilot ballast tank 28 and the secondary ballast tanks 30 connected thereto. Thus, the ballast tanks will become flooded, and the safety platform 12 will sink.

As the platform 12 sinks, the rod 68 of FIG. 4 will follow in a downward direction. As the platform 12 approaches the bottom of the pool, the stop member 92 will engage the second operating sleeve 66 and move it downwardly to return it to its first position illustrated in phantom at 66". Of course, and as explained previously, when this second operating sleeve 66 is returned to its first position, the valve 74 will be returned to its closed position, and the valve 76 will be rotated back to its normally open condition, thereby closing the second diversionary flow path 82 and reopening the outlet flow path 40. Thus, water will then automatically begin to recirculate once more from the pool through the inlet flow path 38, through the filter 36, and back to the pool through the outlet flow path 40. Again, this is accompplished automatically by virtue of the control system hereof.

As previously mentioned, a further feature of the instant invention is the provision of level selection means for automatically establishing a predetermined level within the pool for the platform 12. Such level selection means has been broadly designated as 94 in FIG. and will now be described in detail. The level selection means includes a first pair of stop members or abutment members 98 and 100 which are joined through a substantially U-shaped brace 102, such that these stop members are movable in unison and are adjustably positioned on the rod 56 by means of thumbscrews 104 and 106. In like fashion, a second pair of stop members or abutment members 108 and 110 are joined to one another by a substantially U-shaped brace 112 and are movable in unison and adjustably positionable on the rod 68 by thumbscrews 114 and 116. A rigid bar 118 joins the U-shaped braces 102 and 112.

In operation, depending on the initial location of the platform 12, the operating sleeve 54 or 66 is operated in a manner previously described to position the platform at a predetermined depth in the pool. It will be appreciated of course that as the platform 12 moves to the desired location, the rod 56 and 68 will follow the movement in the manner previously described. At this point in time, while the platform is moving to the desired location, the thumbscrews 104, 106 114 and 116 areloose; the bar 118 held by the user; and the rods 56, and 68 are permitted to pass freely through the collar like stop members 98, 100, 108 and 110.

When the platform 12 reaches the predetermined level (for example, 2 feet from the top of the water level), the thumbscrews 104, 106, 114 and 116 are tightened and the following events will necessarily take place.

Assuming that the platform had initially been on the bottom of the pool and that to reach the two feet level, one had to initially pull down on the first operating sleeve 54; one the thumbscrews are tightened, continued movement of the latform 12 upward past the 2 foot level would cause the collar like stop member of 100 to engage the operating sleeve 54 and return it to its first position 54 (in which case the valves 62 and 64 would revert to their normally open and normally closed positions, respectively and further elevation of the platform 12 would be prevented). Simultaneously, the collar like clamp 110 would move the second operating sleeve 66 to the solid line position of FIG. 4, thereby opening valve 74 and closing valve 76 to permit water to enter the ballast system and begin the sinking process which would return the platform back towards the two foot level. Of course. if the platform went down below the two foot level, collar like stop member 114 would return sleeve 66 to its first position to halt the sinking process, while collar like stop member 98 would move the first sleeve 54 downward towards its second position to reinitiate the platform elevation process. Thus, it will be seen that with the arrangement of FIG. 5, the level selection means will cause the intermittent operation of the first and second 5 operating mechanism 54 and 66 in response to oscillating deviations in the platform elevation from any predetermined desired level. Thus with this feature of the instant invention the depth of the pool can, in effect, be elected and varied. This of couse is of great significance with respect to the enjoyment of a swimming pool by small children, since a relatively deep pool can easily be converted to a wading pool, simply by changing the level of the platform 12.

While this invention has been described with respect to a particular embodiment thereof, numerous others will become obvious to those of ordinary skill in the art in light thereof, and it is preferred, therefore, that the scope of the invention be limited, not by the specific disclosure herein, only by the appended claims.

I claim:

1. A safety system for a swimming pool comprising:

a platform guided for vertical movement in said pool;

a ballast system attached to said platform;

a P p;

an inlet flow path for said pump, one end of said inlet flow path in communication with said pump, the other end of said inlet flow path in communication with the water in said pool;

an outlet flow path for said pump, one end of said outlet flow path in communication with said pump, the other end of said outlet flow path in communication with the water in said pool; whereby said pump can circulate water from said other end of said inlet flow path to said other end of said outlet flow path;

a first diversionary flow path communicating at one end thereof with said inlet flow path and at a second end thereof with said ballast system,

a second diversionary flow path communicating at one end thereof with said outlet flow path and at a second end thereof with said ballast system; and control means operable to control the flow of water in said inlet flow path, outlet flow path, first diversionary flow path, and second diversionary flow path for selectively emptying and filling said ballast system with the water from said pool, whereby said platform may be selectively caused to rise and sink.

2. The safety system of claim 1 wherein said control means includes a first operating mechanism movable between first and second positions when it is desired to draw water from from said ballast system and raise said platform;

a first normally open valve positioned in said inlet flow path and movable to a closed position in response to the movement of said first operating mechanism between its first and second position;

a second normally closed valve positioned in said first diversionary flow path and movable to an open position in response to the movement of said first operating mechanism between its first and second position;

whereby movement of said first operating mechanism to its second position will cause water to be drawn from said ballast system and through said first diversionary flow path to said outlet flow path.

3. The safety system of claim 2 and further including first follower means responsive to the movement of said platform for returning said first operating mechanism to its first position when said platform reaches a first predetermined level;

whereby said first valve will be returned to its normally open status and said second valve will be returned to its normally closed status and water will circulate from said other end of said inlet flow path, to the other end of said outlet flow path when said platform reaches said first predetermined level and said first operating mechanism returns to its first position.

4. The safety system of-claim 3 wherein said first follower means includes a first rod linked to said platform for movement therewith; and said first operating mechanism includes a first sleeve slidable on said first rod between its first and second position, said first rod including an interference member which engages said first sleeve and returns it to its first position in response to said'platform reaching said first predetermined level.

' 5. The safety system of claim 2 wherein said contro means includes a secondoperating mechanism movable between first and second positions when it is desired to pump water into said ballast system and sink said platform;

a third normally closed valve positioned in said second diversionary fiow path and movable to an open position in response to movement of said second operating mechanism between its first and second positions;

a fourth normally open valve positioned in said outlet flow path and movable to a closed position in response to movement of said second operating mechanism between its first and second position;

whereby movement of said second operating mechanism to its second position will cause water to be drawn from said inlet flow path and pumped through said second diversionary fiow path to said ballast system.

6. The safety system of claim 5 and further including first follower means responsive to the movement of said platform for returning said first operating mechanism to its first position when said platform reaches a first predetermined level, and further including second follower means responsive to the movement of said platform for returning said second operating mechanism to its first position when said platform reaches a second predetermined level.

7. The safety system of claim 6 wherein said first follower means includes a first rod linked to said platform for movement therewith; and said first operating mechanism includes a first sleeve slidable on said first rod between its first and second position, said first rod including an interference member which engages said first sleeve and returns it to its first position in response to said platform reaching said first predetermined level; and wherein said second follower means includes a second rod linked to said platform for movement therewith; and said second operating mechanism includes a second sleeve slidable on said second rod between its first and second position, said second rod including an interferrnce member which engages said second sleeve and returns it to its said first position in response to said platform reaching said second predetermined level.

8. The safety system of claim 7 wherein said first predetermined level is the top of the pool and said second predetermined level is the bottom of the pool.

9. The safety system of claim 1 and further including level selection means for maintaining said platform at a predetermined desired level in said pool.

10. The safety system of claim 5 and further including level selection means cooperating with said control means for maintaining said platform at a predetermined desired level in said pool, and wherein said level selection means comprises actuating means for intermittently operating said first and second operating mechanism in response to deviations in said platform from said predetermined desired level.

11. The safety system of claim 7 and further including level selection means cooperating with said control means for maintaining said platform at a predetermined desired level in said pool; wherein said level selection means comprises actuating means for intermittently operating said first and second operating mechanism in response to deviations in said platform from said predetermined desired level; and wherein said actuating means includes a first pair of abutment members preselectively positioned on said first rod on opposite sides of said first sleeve and a second pair of abutment members preselectively positioned on said second rod on opposite sides of said second sleeve, said first pair of abutment members connected to said second pair of abutment members.

12. The safety system of claim 1 wherein said ballast system includes a pilot ballast tank communicating with said first and second diversionary flow paths, and a plurality of secondary ballast tanks positioned about said platform and in communication with said pilot ballast tank. 

1. A safety system for a swimming pool comprising: a platform guided for vertical movement in said pool; a ballast system attached to said platform; a pump; an inlet flow path for said pump, one end of said inlet flow path in communication with said pump, the other end of said inlet flow path in communication with the water in said pool; an outlet flow path for said pump, one end of said outlet flow path in communication with said pump, the other end of said outlet flow path in communication with the water in said pool; whereby said pump can circulate water from said other end of said inlet flow path to said other end of said outlet flow path; a first diversionary flow path communicating at one end thereof with said inlet flow path and at a second end thereof with said ballast system, a second diversionary flow path communicating at one end thereof with said outlet flow path and at a second end thereof with said ballast system; and control means operable to control the flow of water in said inlet flow path, outlet flow path, first diversionary flow path, and second diversionary flow path for selectively emptying and filling said ballast system with the water from said pool, whereby said platform may be selectively caused to rise and sink.
 2. The safety system of claim 1 wherein said control means includes a first operating mechanism movable between first and second positions when it is desired to draw water from from said ballast system and raise said platform; a first normally open valve positioned in said inlet flow path and movable to a closed position in response to the movement of said first operating mechanism between its first and second position; a second normally closed valve positioned in said first diversionary flow path and movable to an open position in response to the movement of said first operating mechanism between its first and second position; whereby movement of said first operating mechanism to its second position will cause water to be drawn from said ballast system and through said first diversionary flow path to said outlet flow path.
 3. The safety system of claim 2 and further including first follower means responsive to the movement of said platform for returning said first operating mechanism to its first position when said platform reaches a first predetermined level; whereby said first valve will be returned to its normally open status and said second valve will be returned to its normally closed status and water will circulate from said other end of said inlet flow path, to the other end of said outlet flow path when said platform reaches said first predetermined level and said first operating mechanism returns to its first position.
 4. The safety system of claim 3 wherein said first follower means includes a first rod linked to said platform for movement therewith; and said first operating mechanism includes a first sleeve slidable on said first rod between its first and second position, said first rod including an interference member which engages said first sleeve and returns it to its first position in response to said platform reaching said first predetermined level.
 5. The safety system of claim 2 wherein said control means includes a second operating mechanism movable between first and second positions when it is desired to pump water into said ballast system and sink said platform; a third normally closed valve positioned in said second diversionary flow path and movable to an open position in response to movement of said second operating mechanism between its first and second positions; a fourth normally open valve positioned in said outlet flow path and movable to a closed position in response to movement of said second operating mechanism between its first and second position; whereby movement of said second operating mechanism to its second position will cause water to be drawn from said inlet flow path and pumped through said second diversionary flow path to said ballast system.
 6. The safety system of claim 5 and further including first follower means responsive to the movement of said platform for returning said first operating mechanism to its first position when said platform reaches a first predetermined level, and further including second follower means responsive to the movement of said platform for returning said second operating mechanism to its first position when said platform reaches a second predetermined level.
 7. The safety system of claim 6 wherein said first follower means includes a first rod linked to said platform for movement therewith; and said first operating mechanism includes a first sleeve slidable on said first rod between its first and second position, said first rod including an interference member which engages said first sleeve and returns it to its first position in response to said platform reaching said first predetermined level; and wherein said second follower means includes a second rod linked to said platform for movement therewith; and said second operating mechanism includes a second sleeve slidable on said second rod between its first and second position, said second rod including an interference member which engages said second sleeve and returns it to its said first position in response to said platform reaching said second predetermined level.
 8. The safety system of claim 7 wherein said first predetermined level is the top of the pool and said second predetermined level is the bottom of the pool.
 9. The safety system of claim 1 and further including level selection means for maintaining said platform at a predetermined desired level in said pool.
 10. The safety system of claim 5 and further including level selection means cooperating with said control means for maintaining said platform at a predetermined desired level in said pool, and wherein said level selection means comprises actuating means for intermittently operating said first and second operating mechanism in response to deviations in said platform from said predetermined desired level.
 11. The safety system of claim 7 and further including level selection means cooperating with said control means for maintaining said platform at a predetermined desired level in said pool; wherein said level selection means comprises actuating means for intermittently operating said first and second operating mechanism in response to deviations in said platform from said predetermined desired level; and wherein said actuating means includes a first pair of abutment members preselectively positioned on said first rod on opposite sides of said first sleeve and a second pair of abutment members preselectively positioned on said second rod on opposite sides of said second sleeve, said first pair of abutment members connected to said second pair of abutment members.
 12. The safety system of claim 1 wherein said ballast system includes a pilot ballast tank communicating with said first and second diversionary flow paths, and a plurality of secondary ballast tanks positioned about said platform and in communication with said pilot ballast tank. 